Jessica starts counting at 30, and she counts by threes. If 30 is the 1st number that Jessica counts. what is the 8th number that she counts?
What is the first number that she counts? $30$ What is the second number that she counts? $\begin{align*}&30 + 3 \\ &= 33\end{align*}$ What is the third number that she counts? $\begin{align*}&30 + 3 + 3 \\ &= 30 + (2 \times 3) \\ &= 36\end{align*}$ What is the 8th number that she counts? $\begin{align*}&30 + (7\times3) \\ &= 30 + 21 \\ &= 51\end{align*}$